A float connected to a pivoted arm is often used to control a water inlet valve when it is desired to regulate the water in a container. The float responds to the water level by exerting a force on the end of the arm. This force on one end of the arm may by used at the other end, with the aid of the pivot, to turn off the inlet valve. The position of the float, relative to the container, at the time the lever causes the inlet valve to turn off, determines the regulated water level. Two examples of such use of floats are the common household toilet and livestock waterers.
The common toilet, in particular, has a flush toilet tank system that is a significant user of water. It has long been desired to cause the toilet to be a more efficient user of water. One line of effort, in this direction, has been to simply lower the regulated water level or, equivalently, decrease the tank volume by placing bricks or other objects inside the tank. However, these efforts are not entirely successful because there are times when a larger volume of water is desired for the flush cycle.
Therefore another line of effort has been directed towards making the water level, set in the toilet tank, adjustable to the need of the moment. An invention capable of easily adjusting the water level would be more responsive to the needs of the user and still help to conserve water.
Accordingly, a large number of inventions have been devised with this object in mind. U.S. Pat. No. 3,945,057 to Therkelsen has a float arm that is hinged in the middle. The outer portion of the arm connects to a short pivoted lever which has a shoulder. This shoulder can be caught on a stop located on the inner section of the arm and in this configuration the outer portion of the float arm is held in a lower position which results in the toilet tank filling to a lower level. The pivoted lever can be pulled upward towards the tank lid, against the force of gravity, so as to cause the shoulder to come off of the stop. This allows the outer portion of the float arm to assume a higher position and, hence, the toilet bowl is filled to a higher level.
U.S. Pat. No. 4,120,055 to Mormile also has a hinged float arm. The float is designed so that the rising water causes it to swing inwards to a position where the force on the float locks it into a lower position. A lever, whose outer end is pulled upwards towards the tank lid, can force the float and the outer section of the arm, outside of the hinge point which allows the float to rise to a higher position.
U.S. Pat. No. 4,700,413 to Lopez describes a hinged float arm in which the outer section of the arm has a short pivoted lever that is caught on a stop, located on the inner section of the arm, so as to hold the float in a lower position. When the lever is lifted towards the tank lid and off of the stop, the float rises to a higher position. In another embodiment, a pivoted lever on the inner section of the hinged float arm has a notch that catches a pin on the outer section. Pulling the arm with its notch upwards and free of the pin creates the second float position.
Other more complex inventions for an adjustable water level are U.S Pat. No. 4,296,505 to Chien-Sheng and U.S. Pat. No. 4,406,024 to Chiu. These two inventions utilize arms, levers, pivots, secondary floats, telescoping arms, and spring loaded detents to achieve adjustable water levels.
While the inventions summarized above are capable of adjusting a regulated water level in a container, such as a toilet tank, they either are complex, involving several moving parts, or the control force direction required to set them to the secondary float position is upward towards the toilet tank lid which leads to a clumsy arrangement for the user.
Thus it can be seen that an apparatus capable of setting two positions for the float in a water level control system that is also simple, requires few moving parts and is easily and naturally controlled outside the tank by the user would be of considerable utility.